Wpo-08 Wcdma Site Survey

7/27/2019 Wpo-08 Wcdma Site Survey

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Content

Overview

Site Survey and Design Basics

WCDMA Site Survey

Focus of Site Survey and Design



Overview

Principles and methods for site survey of WCDMAradio network is basically the same as 2G system.

Due to the self-interference feature of WCDMA

system, reasonable site address planning is

extraordinarily important for a wonderful networkperformance.

WCDMA site survey need to concern the station

sharing with 2G system and interference separation

issues.



Position of Site Survey and Design in

Network Planning Process

investigation

Analysis

Simulation

modeling

Survey

Requirement

analysis

Scale

estimation

Site survey and

design

Transmitting

model test

Transmittingmodel

correction

Output planning report

Network

simulation

Network planning process

Detailed

planning

Network simulation is the

guide and verification for

site survey;

Site survey is the actual

implementation of site

topology structure in

network simulation.

Both of them take the

other as reference,

through repeated

verification, until the

preset aim of networkplanning is fulfilled.



Content

Overview


WCDMA Site Survey




Basic Principle for Site Address Selection

Site address selection for BS：Determine first thebackbone site, and then the local site. Complete first

the coverage for network structure, and then

coverage for specific scenarios.

Try to meet the ideal position specified by cellular

mesh in radio network communication theory. The

deviation should be alternative as much as possible

around 1/4 of the BS coverage radius for the cell

division and network development in the future.

This is a basic principle for network planning, and its

aim is to determine the overall structure of the

network.



Method for Site Address Selection

Screening in accordance with coverage andcapacity requirement

Screening in accordance with the geographical

environment around

Screening in accordance with the radio environmentof the site address

Screening based on existing resources



Screening in accordance with coverage and

capacity requirement

Site address must be selected for primary coveragearea.

Site address must be selected for streets in central

urban area.

BS deployment position must have clear coverageaim.

BS deployment position should be as much as

possible close to the traffic concentration point.

After site selection for “primary” area is completed,perform the large-area continuous coverage for

“secondary” areas.

Expand from the “searching circle” that made up of

key stations.





Coverage： According the specific condition, to achieve multi-form coverage through “point”, “line”, and “area”. BS addressselection need to concern firstly the coverage for key areas,hot areas, high traffic density areas, and important roads andtransportation lines.

Quality：

Switching：ensure the success rate of switching. Cell respiration：to avoid the use of cell respiration.

Load：make full consideration to load margin, generallymargin of 40％～ 60％ should be kept.

Capacity： At the early planning stage, capacity has been

fully considered to avoid frequent expansions. Simplified capacity expansion：expansion without station

increase, smooth expansion.

Indoor coverage：indoor coverage need to be fully considered,and it should equal with that of outdoor coverage





The guiding principle for planning strategy is toensure effective coverage and fully absorb traffics.

Its premise is to divide area levels reasonably.

Area level is determined by geographical

environment and traffic distribution.





“area” is the area that continuously connected ---with a certain traffic (service) requirement, and we

call it “area” coverage.

Meet the requirement of mass people＝ satisfaction straightly rises

＝ income straightly rises



Reasonable

distribution

Unreasonable

distribution





Screening in accordance with the

geographical environment around

Free space Signal fades 20 dB/ 10 times

the distance

Reflection

If phase of the reflection wave

is reverse, there will be offsetfunctions to the direct wave,which reduced the receivingpower

Signal fades 30-40 dB/ 10

times the distance, 10 dB /2times the distance

Diffraction

Direct wave is blocked

With additional loss

diffraction

Partial reflection

B

A

d

D

Free space



Screening in accordance with the

geographical environment around

Basic mechanism：Diffraction Computation method：Statistics

Building/vehicle

penetration loss

?

?

?area Dense urban urban

subur

b

rura

l

vehi

cleBuilding

penetrationloss

18~25 15~20 10~15 10 6

Typical value for building penetration loss



Screening in accordance with the radio

environment

To avoid site address selection near stronginterference sources like mass-power radio station,

radar, satellite ground station, etc.

When sharing address with different system, enough

vertical separation space need to be ensured; for

example, address sharing with GSM1800Mhz

To avoid site address selection near national

security departments.




Different BS types can be selected according the resource

condition Macro station

For large/medium traffic areas, it will be divided into indoor and outdoor patterns, which is of power processingcapability

Micro station

For small traffic areas, it is of small volume and flexibleinstallation.

Baseband pool

Provide only baseband processing function, used inconjunction with RRU

RRU Radio remote unit, generally connected with donor station

(macro station or baseband pool) through fiber. Donor station provides baseband function, while RRU completethe radio function. It is of small volume and flexibleinstallation.



……

RRU

RRU

RRU

RRU

RRU

RRU……

……

……

……

……

fiber fiber

feeder


Macro station for local coverage, the left capacity is expanded through

RRU. Convert the “concentrated” capacity to “spreaded” coverage. Distributed coverage

As RRU is of small volume and flexible installation, it can bypassthe equipment room

Bottlenecks caused by resource, unnecessary to rebuild new

equipment room. Directly connect to donor station (baseband pool or macro station)

through fiber, whose processing capability is generally stronger than micro stations

Through flexible network distribution, the blind coverage arearesulted from building blocks in dense urban area can be solved.



Items need to avoid while site address

selection

While planning WCDMA network, circle distributionof BS must be avoided, as it can easily cause pilot

frequency pollution.



RFD


selection

There should be no blocking around the station

Short-distance blocking has very big effect to the BS

coverage. Shadow will appear on the back of the blocker tocause blind coverage point; while reflection signal from

front of the blocker will cause unnecessary interference to

the system. Generally, there should be no buildings who

are 5m higher than local building in 100m scope around the

station, and no larger high buildings in the 200m scope.




selection

While planning WCDMA network, avoid large-traffic“objects” at remote end of the station.



While planning WCDMA network, avoid thecircumstance of high-low station, as it may easily

cause “station cover station” issues, and thus

appear cross-district coverage.

BS

BS coverage area

Neighbor BS

R1 R2


selection



Experience Summary for Site Address

Selection

BS address selection should firstly consider the coverage for key

areas, hot areas, dense traffic areas, and important roads andtransportation lines.

Reasonably set antenna height, downtilt and direction angle, so as toreduce pilot frequency pollution, control the scope of switching area,and avoid the mutual interference among different systems.

Avoid frequently-switched area being located in key areas, hot areas,

and dense traffic areas. Avoid the too large soft handover rate and hard network interference

control caused by too dense stations.

Keep the antenna height in a same area basically the same, andavoid the circumstance of stations being too high.

Balance inter-cell traffics.

Enhance network coverage through serialized BS supplementation.

Optimize the network through test after network is built.

Network performance of WCDMA is closely related to the BS planningand distribution. A fine network planning can largely reduce thedifficulty and strength in future network optimization.



Signal source Selection

Macro station micro station BBU+RRU

Urban Suburb Sea

Indoor

Airport

Tunnel Stadium Railway

Highway

Bridge



Station model design

BS sector

configurati

on

Adaptive principle Typical area

Omni

station

For the relatively flat terrain, low traffic area Rural area

Single-

sector/dou

ble-sector

For areas with clear coverage requirement and

dense traffic

Highway, indoor

coverage, etc

Triple-

sector

Frequently used configuration, to solve the wide

coverage requirement for mass traffic area

Dense urban,

common urban,

suburb, etcOTSR For low traffic, but wide coverage areas

For areas with terrible radio environment, and

where distributed coverage is required

Rural, dense

buildings, etc



Content

Overview


WCDMA Site Survey




BS Information Survey

Main tasks for BS information survey Tools for BS information survey

Required data for BS information survey



Main tasks for BS information survey

Obtain necessary data for radio planning andsimulation

Understand geographical environment of the site

Understand radio environment of the site

Understand station building condition of the site Master traffic distribution in the planning area

Provide candidate station for the planning area



Tools for BS information survey

Collect data through Laser rangefinder The use of laser rangefinder is to obtain the BS

antenna height. Antenna height is the distance from

antenna to ground. In urban area, antenna is usually

built on the ceiling of the building, thus we need to

measure height of the building and height from

antenna to the building ceiling to get the height of

the antenna. When antenna is placed on floor tower,

its height can be directly measured.




Characteristic of laser rangefinder__Leica DISTO Classic5：

Range：from 0.2m to 200m, with measurementaccuracy of 3mm.

Inside telescope：can be used for the measurement of long-distance and accurate target.

Inside bubble：Simplify horizontal measurement

Calculation： Auxiliary measurement with Pythagorean

law, which expanded the scope of use. Tracking measurement, positioning, and determine the

max and min value.

Has store function.

Multi-functional base, measurement can be performedfrom plane and corner.

With backlight lighting, measurement can be performed

in dark room or dim-light place. Small volume, light weight, and easy operation. With

power-saving design, one group of battery can supportmore than 10000 times measurement. Laser indicationcan be used to mark the measurement point.




Functions of laser rangefinder

store

measurement

distance

Continuous measurement

Pythagorean law




GPS refers to the Global Positioning System completely built in

1994. It is made up of space constellation, ground control, anduser equipment.

GPS has 25 satellites at present, which are running around onsix elliptical orbit more than 20 000 Km away from the earth.

Receiver captures and locks satellite signal through phase

tracking, collects the satellite ephemeris, measures pseudo-range, positions and calculates longitude, latitude, and altitudeat the position of the receiver. Captures of 3 satellites canperform 2D positioning, and satellites of more than 4 canperform 3D positioning. The more satellites captured, thehigher will be the positioning accuracy.

Through GPS we can find out the location information of a BS,and display it on simulation electronic map and mapinfo two-dimensional vector map. GPS can also help to get the BSaltitude information, which will be extraordinary data for largeundulating-terrain areas like mountainous area, hills, etc.




Eight pictures for the ambient environment, starting

from the right north, each picture taken in the angle

of 45o

Multiple pictures of ceiling, taken separately based

on the size of the ceiling.

One picture for the appearance of a candidate

building in the site to be selected.

For pictures not taken or with unsatisfactory effect,

try again.




Compass

In radio network survey, the use of compass is to get

the direction angle for BS sector.

Some compasses have the function of measure the

donwtilt angle of the antenna. In engineering practice,

as it is impossible to ensure the holder being straight,the measurement of downtilt angle is extraordinarily

important.

Indicate the photographing direction.




Open a compass and place it flatly. The zero line of the

compass must be in line with the pointer with a dot (as shown

in the red circle ), and the pointer must direct to north

(Magnetic North).

Note：Some compasses have their white needle pointing to

north while some others have their black needle pointing to

north. The end of the pointer with a dot should be the reference.Do not use a compass around the strong magnetic field, and

do not put a compass on a metal platform (including an iron

tower) or near a metal target, because these factors may affect

the positioning precision of the compass.




Measuring the downtilt angle of antenna through

compass: Open the compass, place its straight side

on the back plane of the installed antenna, and

adjust the gradienter with the manipulator behind the

compass until the gradienter is in the level status. In

this case, the scale degree (internal dial) indicatedby the white dot beside the gradienter is the downtilt

angle of the antenna.




YBT250 frequency-clearance test

It has been a common sense that all kinds of signals in thespace can have interference to mobile networks. Theseinterferences make call quality reduce, and cause servicedropping. With the low connection rate, quality of the wholenetwork will be affected.

Frequency resource occupation by the dedicated old radio

system, improper network configuration by different operators,setting problem for transmitting machine, cell overlapping,environment, electromagnetic compatibility, and deliberateinterference are all the factors to generate interference toradios of mobile network communication.

In the network planning, there are two phases in which the

frequency-clearance test should be made: propagation modeltest phase and base-station survey phase. Through such atest, you can test whether the 3 G band has been occupied,which is favorable to the accuracy of the propagation modeltest and the solution of the problem of band use throughcoordination with related units before the commissioning of anetwork.




First, get objective information of the BS, which are BS name,

longitude & latitude, ceiling height, and altitude.

BS number ：Service area abbreviation from two parts＋

sequence number ；

BS name：BS name is place name＋ building name. In

urban area, street name is used for place name; while for

village and town, it will be named after the village and town.

longitude & latitude： Get longitude & latitude information

through GPS；

Ceiling height：the relative height from the ceiling with

antenna to ground, which can be measured by rangefinder. Altitude：GPS will be used to record the altitude (absolute

height) of the BS address.




According the actual survey result, make suggestions to

network planning. Suggested station type：Investigation staff determines the

cellular type (macro cellular, micro cellular) and station type(Omni, directional) according to the survey result.

Suggested antenna parameters：gain, horizontal lobe and

vertical lobe of the selected antenna; directional angle anddowntilt angle of the antenna;

Suggested antenna height：distance from antenna positionto ground; necessity of height increasing, and the heightincreasing method, for example, length of the holder, lengthof the pull tower, height of the higher frame, height of the

floor tower, etc. Suggested separation method and separation distance：

Separation method：horizontal separation, verticalseparation；the unit for separation distance is meter.




After the survey, the survey result need to be found

out, and survey suggestion need to be given.

BS with the shortest distance：record distance and

directional angle; BS in the scope of 2Km need to be

recorded for dense urban areas; 3-5Km for common

urban areas; 5-10Km for rural and suburban areas; If there is no NS in these scopes, just record the

nearest one.

Describe the reason of selecting the BS, and clearly

identify objects in the coverage area.




BS environment description：take pictures of the environmentwith digital camera every 45°of the directional angle, andmake text descriptions at the same time, totally 8 1024*768

environment pictures. Text must match the pictures. Focus onwhether there is blocking in the surrounding environment andthe relative BS height to the surrounding. Building density inthe coverage area, height difference from the BS, direction andwidth of the roads, and the direction, distance and height of theblocking building.

0

° 45°

275

°



Site display in mapinfo

Site display in simulation




Site address sharing is helpful for fast



Site address sharing is helpful for fast

network building and cost reducingTraditional network building has

tremendous dependence to equipmentroom resources

Equipment room resource is an necessary

condition for site address resources

enough site address resource is an

important ensuring to fine coverage

Equipment room becomes the bottleneck of

fast network building

Equipment room resource becomes harder

and harder to obtain

Places suitable for site addresses have been

the competition for various operators

Experiences from commercial bureau and

test bureau indicate that, process of the project

is often limited by the process of obtaining

equipment rooms

Large amount of equipment resource leads to the

increase of network building cost

Rent for equipment room：30 000～50 000/year (rent for

ceiling not included)

Facilities (Air conditioning, power supply ) construction

expenses：about 10 000～30 000

Make full use of 2G site address resource in



Combination of requirement and actual

condition, comprehensive balance.

Sharing of

equipment

room/shelter3G

BS

Sharing of

transmission

bat

ter

y

po

we

r

AC

2G

BS

co

ntr

ol

Sharing

of iron

tower

Sharing

of feeder

window

Sharing of equipment room/shelter

Sharing of power supply/battery

Sharing of transmission

Sharing of iron tower

Sharing of space

Sharing of control system

Sharing of feeder window

Sharing of grounding

Sharing of cable frame


3G construction





3G construction

For space of equipment room, following items need to be

concerned: 1． According to the planning requirement, initially select out

the sites that might perform shared address construction.Meanwhile, consider the capacity expansion requirement in thefuture, and get an initial understanding of the capacity planningfor each station.

2．Perform equipment room resource survey to the siteaddress that might perform address sharing, so as to get thedetailed available space resources of the above stations. Thesurvey of equipment room resource might not only limited to itsavailable space resources, but also relate to thecomprehensive situations of its power system, antenna feeder system, and so on.

3．Collect technical parameters of the equipment that might beused as the initial basis for equipment room space and to judgeif the other conditions can meet the requirement. For 3Gstation, due to its small volume, big capacity, it can be installedaside the wall and easily maintained, which can better suit therequirement for various equipment room conditions.





3G construction

4．Make a using strategy for equipment room. Equipment

room with enough space can be directly listed as the candidatesite address. Those who can meet requirement after simpletransformation can be listed as candidate site address. For theequipment room who cannot meet space requirement, but itssite address is urged by service distribution and networkplanning, we can consider various BS networking solution,such as outdoor BS, remote radio, etc.

5．Consider both outdoor coverage and indoor coverage.Some sites may spontaneously meet the BS equipment roomrequirement for both outdoor coverage and indoor coverage.Thus there will be another choice to reduce equipment roominvestment, since equipment is of enough capacity andcapability.

6．For weighing or equipment room: The entry of 3Gequipment and facilities increased the weighing requirement.Firstly, battery increased, and facilities of power supply alsoincreased. The calculation for weighing need to consider various factors, including capacity expansion.



equipment

room/shelter sharing

3G

BS

Sharing

of

transmi

ssionb

at

te

ry

p

o

w

er

A

C

2G

BS

c

o

nt

ro

l

共铁塔

Sharing offeederwindow

Advantages：

1) equipment room/shelter sharing is the basis for sharing other facilities

2) Shelter takes a large percentagein the facility investment, thus shelter sharing can largely reduce the cost

3) Equipment renting is very timeand effort-consuming, which is of big

effect to the engineering processEquipment sharing can largely speedup the engineering process

Cautions for equipment/shelter sharing：

1) whether there is available space

for equipment room/shelter 2) whether there are specific

weighing requirement

3) Take into consideration thetemperature, humidity, earthquakeprotection, etc.

2G 3G equipment room/shelter sharing



共机房/方舱

3G基站

共传输

蓄

电池

电

源

空

调

2G

基站

监

控共铁塔

共馈线窗

2G 3G power/battery sharing

Considerations for power/battery

sharing： 1） AC：power cable, air switch,

power facilities, etc. Transformation

need to be performed if loading

capacity is too low.

2）DC：No power cabinet is generally

needed for site sharing, only a newpower module will be fine.

3） Add new battery group according

to power-down time requirements and

equipment power loss. equipment

room/shelter sharing

3G

BS

Sharing

of

transmi

ssion A

C

2G

BS

共铁塔

Sharing offeederwindow



2G 3G power/battery sharing

1．For AC power facility, a characteristic of 3G BS is to have larger full-loadpower than that of GSM. While site address sharing, larger load capacityrequirement are raised for the original power equipment. For those equipmentroom whose original power facilities cannot meet requirement, transformationneed to be performed, and power cable, air switch, and facilities might also beinvolved.

2．For DC power facility, capacity expansion might be needed for the originalpower facilities. While capacity expansion, The operational power requirementof 3G BS, and requirement of battery at the worst conditions need to beconsidered.

3．Battery configuration: for site address usually with batteries, the capacitydistribution of battery need to be considered. When all the battery power isshared by GSM BS and WCDMA BS, due to the relatively larger power of 3GBS, the power-down time of GSM BS will be affected. For the circumstancewhen powers of ＋24V and－48V coexisting in GSM BS and WCDMA BS,battery need to be independently configured. At this moment, battery capacityfor WCDMA BS need to be independently considered.

4．During the engineering of shared-site address construction, as 3G and 2Gequipment might not be manufactured by one factory, parameters of theequipment might be different. Therefore, these factors must be considered,and capacity expansion need to be performed to existing power equipment if necessary.



2G 3G Transmission

For each Node B, estimate the required 3G

transmission bandwidth according to the traffic of 2G,

and determine the sharing combined with the

existing transmission margin.

After collecting all the Node B site addresses and

capacity, combined with transmission of the existingnetwork, planning for the shared part and newly-built

part can be made. At the early stage of 3G network

building, as traffic is not large, we can consider to

use as much as possible the existing transmissionnetwork.



Sharing of iron

3G antenna

2G antenna

Sharing of feeder

window

Sharing of cable

frame

Sharing of feeder window and

cable frame

Sharing of

conrol

Sharing of AC

Sharing of other facilities





Grounding system: for WCDMA BS, the grounding requirement is the

same as GSM, that is to say, the grounding impedance should be lessthan 5 Ohm. Therefore, the fulfilled groundings in the original GSMcan be directly used. As to indoor, outdoor, and prepare-to-usedconditions, we need to consider if there is still available grounding inthe original one. In the actual practice, we also need to pay attentionthe grounding method, so as to avoid the bad groundings due to theuse for quite a long period.

Iron tower and holding: When antenna is installed on the iron tower or the higher frame on the top of building, no new equipment need to beadded as iron tower and higher frame can be shared most of thecases. Considering the separation between 2G and 3G antennas, andthe planed height for 3G antenna, if the relative separation condition isnot fulfilled, holding or new higher frame will need to be added.

Antenna feeder system: for the circumstance of small ceilingenvironment, repeated antenna and antenna holding construction, wewill share the antenna, and use antennas that support both 2G and3G at the same time for a better construction efficiency.

3G BS distribution Station-sharing



3G BS distribution—— Station-sharing

construction by using 2G resources

2G is usually limited by capacity in

dense urban/common urban area. Itsstation density is larger than 3G, whichcan be selected by3G.

Perform reasonable network topologydesign on the basis of 2G according tothe cell coverage radius of 3G network,and select the most suitable 2G stations

for 3G network construction. As the existing 2G station might not fully

comply with the cellular systemstructure, there will be more 3G stationsthan the number from scale estimation.

Station sharing might cause number increasing for the actual 3G stations.

Does this mean the cost will also be increased?

Newly planed 3G station

Existing 2G station that planed for 3G

Existing 2G station that not planed for 3G



Network coverage example for ××city Through 2G network investigation, in order to make full use of 2G

resources, station number for ××city is as follows：

After actual investigation, if weperform station distribution based onthe early estimated 723-station radius,450 old stations can be used, and273 new stations need to be built.——too many new stations, siteaddresses hard to obtain.

If we use 863 stations, only about 45new stations need to be built. Assumethe investment for new station is 40%,for facilities is 60%, and the cost of the two solution will be respectively：

Cost for 723 stations：723*0.4+273*0.6=453 Cost for 863 stations：863*0.4＋

45*0.6=372.2 The latter construction costs about

83% of the former

Station sharing as much as possible,

to reduce the networking CAPEX

while meeting the requirement of

fast network building！



Current Radio Environment

Rapid progress has been made to the mobile

communication in China in the recent 20 years. Butmobile communication was operated by the country inquite a long period, with single standard, co-existenceand interference issues are not prominent.

When WCDMA is starting for commercial use in China,

many forms cellular communication systems (GSM、DCS、CDMA、PHS、BWA) already exist, andcompetition among multiple operators already formed.Moreover, there are also large amount of satellite groundstations, timing GPS receiving equipments, microwave

transmission equipments, and all these makeinterference become very promiment.



Type of interference

Inner-system interference is the interference from

interference source to receiver

Theoretically, there are four types of interference

Interference by added noise

Interference from intermodulation

Interference from block

Interference from neighbor channel



Requirement for mutual interference

interference(dB)Vertical

distance(m)

Horizontal distance

(ideal)(m)

CDMA800 20 0.3 0.8

CDMA1.9G 84 4 200

CDMA1.9Gplu

s filter 50 0.6 4

GSM900 20 0.3 0.8

DCS1800 20 0.15 0.4

TD 40 0.31 1.3

Space separation is the mostly used solution for mutual

interference

Solution of the mutual interference between



Solution of the mutual interference between

WCDMA and GSM

Separation must be met. There is only 20cm been required for ２／３

Ｇ equipment, and it is easy on engineering.

After sharing tower built, there will easily be antennas of differentfrequency band on the same pulling tower. For this circumstance,

different marks need to be made for the smooth implementation of the

future engineering RF optimization.

Horizontal separation Vertical separation

C f S ifi S i



Coverage for Specific Scenarios

Take high floor residential area for example

Features: high floor, building is mainly with fixture

and concrete, which is of large penetration loss.

Transmission environment for radio signal is quite

band, and blind coverage point will be easily

occurred.

Focus: Residents are sensitive to signal radiation,

camouflage and beautification of antenna is crucial.

Idea: Distributed three-dimension coverage

Wpo-08 Wcdma Site Survey

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